Greenwich Mean Time (GMT) is essential for what purpose?

Greenwich Mean Time (GMT) plays a crucial role as a foundation for calculating various world time zones. GMT serves as the reference point from which all other time zones are defined. When determining local times around the globe, adjustments are made based on how many hours ahead of or behind GMT a specific location is. This is essential for coordinating activities across different regions, particularly in contexts such as travel, communication, and international operations.

The other choices, while they relate to time in various ways, do not accurately capture the primary function of GMT. For example, while meal times can vary greatly across cultures and regions, they do not adhere strictly to GMT. Similarly, although international flights take time zones into consideration, they do not universally operate on GMT alone. Business transactions may align with specific time zones according to local or international business practices rather than strictly following GMT standards.